Locking device for the lid of a pressure vessel

ABSTRACT

A remote controlled locking device comprising a plurality of support legs which are to be applied between a shoulder on a pressure vessel and a shoulder on the lid, which rests on a collar in the vessel. Each leg is pivotably fitted on a support plate, which is movable towards the edge of the lid. A hydraulic slide is arranged to move vertically close to the leg. The slide is connected by means of a link arm to the leg in order to pivot this to and from engagement with the shoulder The slide is connected by means of a spring loaded link arm to the plate to move this towards the edge of the lid so that a wedge on the slide can engage the plate to tighten up the leg.

United States Patent [191 Johnsson [11'] 3,856,338 [451 Dec. 24, 1974 LOCKING DEVICE FOR THE LID OF A PRESSURE VESSEL [75] Inventor: Erik Borje Johnsson, Trosa, Sweden [73] Assignee: Aktiebolaget Atomenergi,

Stockholm, Sweden [22] Filed: Apr. 18, 1973 21 Appl. No.: 352,224

[30] Foreign Application Priority Data May 26, 1972 Sweden; 6988/72 [52] U.S. Cl 292/256, 292/201, 292/256.65 [51] Int. Cl B6Sd 45/00 [58] Field of Search 292/256, 256.6, 256.65,

[56] References Cited UNITED STATES PATENTS 2,274,319 2/1942 Chesterman 292/256 X 2,734,824 2/1956 DeLuca 292/201 X 2,776,854 l/l957 Billstrom 292/256 2,786,704 3/1957 Presdee et al. 292/256 2,834,504 5/1958 Annicq ..292/201X 3,353,859 11/1967 Schupack ..292/256 Primary ExaminerRoy D. Frazier Assistant Examiner-Peter A. Aschenbrenner Attorney, Agent, or FirmToren, McGeady and Stanger 1 [57] ABSTRACT A remote Controlled locking device comprising a plurality of support legs which are to be applied between a shoulderon a pressure vessel and a shoulder on the lid, which rests on a collar in the vessel. Each leg is pivotably fitted on a support plate, which is movable,

towards the edge of the lid. A hydraulic slide is ar- 10 Claims, 2 Drawing Figures PAIENIEB 3.856.338

snm 1 OF 2 PATEHTED UEE24|974 SHEET 2 2 I The present invention relates to a locking device for the lid of a pressure vessel, comprising a'plurality of support legs arranged along the circumference of the lid, a shoulder on the lid for the lower end of the support legs and a shoulder on the pressure vessel for the upper end of the support legs. The invention relates primarily to a large pressure vessel of prestressed concrete, particularly intended for a nuclear reactor.

It is already known from Swedish Pat. No. 324,190 to firmly lock the lid of a pressure vessel with the help of support legs which press the lid down against a seat in the vessel. Such support legs are arranged between the upper side of the lid, obliquely upwards and outwards against a shoulder at the opening of the vessel. The lid is then clamped in position by wedges which are driven between the support legs and the shoulder of the vessel or the lid.

The drawback with clamping the lock inthis way is that the wedges are handled manually to a great extent. This is extremely heavy work and means that applying and removing the lid of a pressure vessel takes a relatively long time. If the vessel is the pressure vessel of a nuclear reactor it is essential to reduce the time when the vessel is open during manipulation since the personnel assembling the lid are in a region which is relatively unprotected against radioactive irradiation.

The problems and drawbacks mentioned above are eliminated according to the invention by a locking device for the lid of a pressure vessel, comprising a plurality of support legs arranged along the circumference of the lid, a shoulder on the lid for the lower end of the support legs and a shoulder on the pressure vessel for the upper end of the support legs, which is characterised in that the lower end of the support leg is pivotably fitted on a support plate, that the support plateis movable perpendicularly to the circumference of the lid,

that a hydraulically or pneumatically driven slide is arranged to be movable substantially vertically close to the support leg, that the slide is connected by means of a link arm to the support leg in order to pivot this to engage or disengage with the shoulder on the pressure vessel, that by means of a sprung or spring loaded link arm the slide is connected to the support plate to move the support plate perpendicularly outwards towards the circumference of the lid to tighten up the support leg and to permit a wedge to be applied against the support plate, and that the wedge is arranged to be moved by the slide into engagement with the support plate to force this into a position where the support leg is tightly clamped between the pressure vessel and the lid and to lock the support plate in this position.

A support ring is suitably loosely applied on the peripheral shoulder of the lid.

The slide is suitably permanently connected to a hydraulic or pneumatic cylinder, the piston rod of which is fitted against the ring, and is arranged to run along the piston rod. The oblique surface of the wedge is preferably provided with a replaceable layer.

If a toroid seal is arranged between the lid and a sealing seat on the vessel so that the toroid seal has an outer ring flange clamped against the sealing seat with the help of a plurality of yokes, the toroid seal may have an inner ring flange applied between the ring and the sealing engagement against the lidwhen the locking device is tightened up.

The ring, together with the locking devices, can be lifted from the lid in order to allow convenient manipulation of a seal below the ring and the support plate is preferably controlled by a guide strip arranged perpendicular to the circumference of the lid, on the ring.

shoulder of the lid so that the ring flange is clamped to A yoke, which is applied against the slide and the lid after the lid has been clamped, may be arranged on the lid to prevent the slide from unintentionally lifting.

The cylinders l are preferably parallel-connected to a source of pressure medium, so that all the support legs are applied with thesame pressure. I

The invention will be described in detail in the following by way of example with reference to the accom-, panying' drawings.

FIG. 1 shows a locking device according to the invention for the lid of a pressure vessel in open position and FIG. 2 shows the same device in locked position.

FIG. 1 shows the well of a cylindrical reactor vessel 29 and a lid 25 for this vessel. A ring 3 around the periphery of the lid 25 rests against a shoulder 25a in the lid. The locking device according to the invention is fitted on the ring 3. A support leg 10 included in the locking device is intended to clamp the lid against an annular seat in the wall of the vessel when it comes into engagement with a shoulder 27 in the vessel 29.

The locking means comprises a hydraulic cylinder 1, the piston 2 being fixed, for example screwed, to the ring 3, on which the locking'devices are fitted. A slide 4 is arranged around the piston rod 2 and is attached to the cylinder 1. The upper part of the slide 4 is designed as a spacer 5 and at its central part there is an L-shaped link-arm bearing 6. The lower part of the slide is in the form of a wedge 7, the oblique surface facing the support plate 8 being provided with a replaceable layer 7a.

A lower support plate 8 which is radially displaceable is movably arranged on the ring 3 and runs on a radial guide rail 9 arranged on the ring 3. I

The upper part of the support plate 8 is cup-shaped to fit the rounded lower end of the support leg 10 so that they fit well together even if the inclination of the .support leg alters somewhat.

A wedge surface 80, fitting the wedge surface 70, is arranged on the end of the support plate 8 facing the piston rod 2. The wedge surface 8a has a central, vertical, cylindrical recess so that the support plate can lie flush with the piston rod 2 without tilting.

The support plate 8 is provided with two lugs 11 directed upwardly, in which substantially vertical grooves 12 have been provided. The lower end of the support leg 10 is provided with two pins 13 which fit into the grooves 12 so that the end of the support leg is held in the correct position with respect to the cup-shaped part of the support plate. At approximately the centre of its lower half, the sup port leg 10 is provided with a pin 15 for a link arm 14 to adjust the angular position of the support leg. The lowerend of the link arm is pivotably mounted about the pin 15. A stop 16 is arranged on the support leg in order to limit the clockwise rotation of the link arm to approximately out from the support leg.

The upper part of the link arm 14 is provided with a horizontal pin 17 perpendicular to the longitudinal direction of the link arm. The pin 17 engages in the L- shaped link-arm bearing 6 on the slide 4 when the support leg is operated.

An axially sprung that is, spring loaded link arm 18 is pivotably mounted at its first end about a pin 19 at the lower righthand part of the wedge 7 on the slide 4. The other end of the link arm 18 is fork-shaped and is guided by a pin 20 on the top righthand part of one of the lugs 11.

An upper support plate 21, shaped to fit the upper end of the support leg 10, is arranged on the shoulder 27 of the pressure vessel 29. The support plate 21 is provided with a blocking edge 22 for the support leg.

The ring 3 rests on an inner ring flange 24 of a toroid seal 23 and clamps this tightly against the shoulder 25a of the lid 25. During the wedging process the wedge 7 rests against the blocking surface 25b of the lid.

At their upper ends the cylinders are provided with an'assembly hook 26 which can be used to lift the ring 3 with the support legs and locking device as an easily handled unit. It is then easy to reach the toroid ring 23 for manipulation. It can also be used to pull up the wedge if the hydraulic pressure is not sufficient.

Around the edge of the opening of the pressure vessel 29 is a shoulder 27 against which the support plate 21 is fitted. A yoke 28 is arranged on the lid in order to keep the slide in depressed position.

The following is a description of the events when a support leg is applied between the lid and the pressure vessel by means of the locking device according to the invention.

To start with the support leg is drawn in towards the centre of the lid so that the ring 3 with the locking devices can be lifted on and off without obstruction (FIG. 1).

When a support leg is to be applied, .the minus side of the cylinder 1, i.e., the chamber below the piston 2a of the cylinder, is supplied with pressure medium. The slide then moves together with the cylinder 1 down.- wardly along the piston rod 2. The support plate 8 is pressed against the piston rod 2 because the supportleg inclines outwardly and its centre of gravity is above the journalling pin of the link arm 14. During the first part of the downward movement of the slide 4, therefore, the support plate 8 is stationary and the support leg can pivot about its lower shaft pins 13 sincethe attachment 17 of the link arm 14 moves downwards. The

support leg 10 tips outwards about the journalling in the support plate 8, guided by the movement of the link arm 14, until the upper end of the support leg comes into contact with the blocking edge 22 of the support plate 21.

The angular movement of the support leg terminates here, but during this stage the -forkshaped end of the link arm 18 has slipped so far over the pin on the lug 11 that the pin 20 and the fork-bottom of the link arm- 18 are in contact with each other. When the slide 4 is moved still further down, the link arm 18 presses the support plate 8 to the left, with the result that the support leg is moved substantially axially against the upper support plate 21. The link arm 18 has the task of moving the support plate to the left at this stage so that the wedge 7 can be applied against the wedge surface 8a of the support plate 8. The wedge surface 7a of the wedge 7 is slightly inclined since the wedges should be selflocking to a certain extent. The support plate 8 is moved to the left with a force determined by the spring force from the compression of the axially sprung or spring loaded link arm 18.

The support leg 10 is thus moved up to loose abut-' ment against the support 21.

During application of the support leg thelink arm 14 has no guiding function after the support leg has made contact with the blocking edge 22 of the support 21, but continues to rotate freely in aclockwise direction about the pin 15 until it is restrained by the stop 16. The pin 17 at the upper end of the link arm 14'then moves freely upward and to the right in relation to the link-arm bearing 6 as the slide 4 continues its downward movement.

The link arm 18 presses the support plate so far to the left when the pin 19 approaches the level of the pin 20' that the wedge surface 7a of the wedge 7 can come into contact with the wedge surface 8a of the support plate 8. The link arm 18 hasno function in the rest of the locking process.

' The wedge 7 is then forced further down and, with the help of the support surface 25b of the lid 25, presses the plate 8 outwards with the pressure considered necessary to satisfactorily-seal the pressure vessel lid (FIG. 2). This pressure is determined by the supply pressure and piston area of the cylinder 1.

The wedge 7, and thus the support plate 8 and support leg 10, can then be locked by a yoke 28 which is applied against the horizontal surface of the link-arm bearing 6 and a horizontal bearing surface on the lid 25. Theyoke is clamped by means of a central bolt.

- When the lid is to be removed, the yoke is removed first, after which the plus side of the cylinder, i.e., the chamber above the cylinder piston 2a is supplied with pressure medium. Thewedge 7 then moves up and the support plate 8 moves to the right. The support'leg is thus unloaded. Further upward movement of the slide 4 releases the wedge surfaces 7a and from each other so that the support plate 8, spring-controlled by the link arm 18, moves towards the piston rod 2 and so that the pin 17 of the link arm 14 comes into contact with the link-arm bearing 6. A continuedupward movement of the slide causes the support leg 10 to be angled inwardly towards the centre of the lid about the pins 13 by means of the link arm 14 which is guided by the upward movement of the link-arm bearing, i.e., the slide 4, until the initial position shown in FIG. 1 is reached. Ring, locking device and lid are then lifted up. Alternatively, the ring may be lifted from the lid 1 together with the locking devices so that the toroid seal 23 can be conveniently manipulated.

The arrangement can obviously be modified in many ways within the scope of the basic idea of the invention. For example, the bottom ring of the locking device might be increased peripherally and provided with jointed support pins to clamp the outer ring flange of the toroid seal against the sealing edge of the vessel. If then the inner ring flange of the toroid seal is screwed to the bottom ring of the locking device, the lid can be removed immediately after removal of the locking device. It is important, however, for the locking device to be remote-controlled and, when a toroid seal is arranged between the bottomring of the locking device and the lid, for it to clamp at least the inner ring of the toroid against the lid, as well as being easy to lift off to permit convenient access to the toroid seal.

What is claimed is:

1. Locking device for the lid of a pressure vessel, comprising a plurality of support legs arranged along the circumference of the lid (25), a shoulder (25a) on the lid for the lower end of the support legs and a shoulder 27) on the pressure vessel (28) for the upper end of the support legs, characterised in that the lower end of the support leg is pivotably fitted on a support plate (8), that the support plate (8) is movable perpendicularly to the circumference of the lid, that a hydraulically or pneumatically driven slide (4) is arranged to be movable substantially vertically close to the support leg (10), that the slide (4) is connected by means of a link arm to the support leg (10) in order to pivot this to engage or disengage with the shoulder (27 on the pressure vessel, that by means of a spring load link arm (18)the slide is connected to the support plate (8) to move the support plate perpendicularly outwards towards the circumference of the lid to tighten up the support leg and to permit a wedge (7) to be applied against the support plate, and that the wedge (7 is arranged to be moved by the slide (4) into engagement with the support plate (8) to force this into a position where the support leg (10) is tightly clamped between the pressure vessel and the lid and to lock the support plate in this position.

2. Locking device according to claim 1, characterised in that a support ring (3) is applied loosely on the peripheral shoulder (25a) of the lid (25).

3. Locking device according to claim 1, characterisedin that the slide (4) is permanently connected to a hydraulic or pneumatic cylinder (1), the piston rod (2) of which is fitted against the ring (,3).

4. Locking device according to claim 1, characterised in that the slide (4) is arranged to run along the piston rod (2).

5. Locking device according to claim 1, in which a toroid seal (23) is arranged between the lid (25) and a sealing seat on the vessel (29) so that the toroid seal (23) has an outer ring flange clamped againstthe sealing seat by means of a plurality of yokes, characterised Y in that the toroid seal (23) has an inner ring flange (24) applied between the ring (3) and the shoulder (25a) of the lid (25), so that the ring flange (24) is clamped to sealing engagement against the lid 25 when the locking device is'appliedr 6. Locking device according to claim 4, characterised in that the ring (3), together with the locking devices, can be lifted from the lid (25) in order to allow convenient manipulation of a seal (23) below the ring (3).

7. Locking device according to claim 1, characterised in that the support plate (8) is controlled by a I guide strip (9) arranged perpendicular to the circumference of the lid, on the ring (3). v

8. Locking device according-to claim 1, characterised in that a yoke (28) which is applied against the slide (4) and the lid (25) after the lid has been clamped, is arranged on the lid (25) to stop the slide (4) from being unintentionally lifted.

9. Locking device according to claim 2, characterised in that the cylinders (1) are parallel-connected to a source of pressure medium so that all the support legs (10) are applied with the same pressure.

10. Locking device according to claim 1, characterised in that the oblique surface of the .wedge (7 is provided with a replaceable layer 

1. Locking device for the lid of a pressure vessel, comprising a plurality of support legs (10) arranged along the circumference of the lid (25), a shoulder (25a) on the lid for the lower end of the support legs and a shoulder (27) on the pressure vessel (28) for the upper end of the support legs, characterised in that the lower end of the support leg is pivotably fitted on a support plate (8), that the support plate (8) is movable perpendicularly to the circumference of the lid, that a hydraulically or pneumatically driven slide (4) is arranged to be movable substantially vertically close to the support leg (10), that the slide (4) is connected by means of a link arm to the support leg (10) in order to pivot this to engage or disengage with the shoulder (27) on the pressure vessel, that by means of a spring load link arm (18) the slide is connected to the support plate (8) to move the support plate perpendicularly outwards towards the circumference of the lid to tighten up the support leg and to permit a wedge (7) to be applied against the support plate, and that the wedge (7) is arranged to be moved by the slide (4) into engagement with the support plate (8) to force this into a position where the support leg (10) is tightly clamped between the pressure vessel and the lid and to lock the support plate in this position.
 2. Locking device according to claim 1, characterised in that a support ring (3) is applied loosely on the peripheral shoulder (25a) of the lid (25).
 3. Locking device according to claim 1, characterised in that the slide (4) is permanently connected to a hydraulic or pneumatic cylinder (1), the piston rod (2) of which is fitted against the ring (3).
 4. Locking device according to claim 1, characterised in that the slide (4) is arranged to run along the piston rod (2).
 5. Locking device according to claim 1, in which a toroid seal (23) is arranged between the lid (25) and a sealing seat on the vessel (29) so that the toroid seal (23) has an outer ring flange clamped against the sealing seat by means of a plurality of yokes, characterised in that the toroid seal (23) has an inner ring flange (24) applied between the ring (3) and the shoulder (25a) of the lid (25), so that the ring flange (24) is clamped to sealing engagement against the lid (25) when the locking device is applied.
 6. Locking device according to claim 4, characterised in that the ring (3), together with the locking devices, can be lifted from the lid (25) in order to allow convenient manipulation of a seal (23) below the ring (3).
 7. Locking device according to claim 1, characterised in that the support plate (8) is controlled by a guide strip (9) arranged perpendicular to the circumference of the lid, on the ring (3).
 8. Locking device according to claim 1, characterised in that a yoke (28) which is applied against the slide (4) and the lid (25) after the lid has been clamped, is arranged on the lid (25) to stop the slide (4) from being unintentionally lifted.
 9. Locking device according to claim 2, characterised in that the cylinders (1) are parallel-connected to a source of pressure medium so that all the support legs (10) are applied with the same pressure.
 10. Locking device according to claim 1, characterised in that the oblique surface of the wedge (7) is provided with a replaceable layer (7a). 